1. Field of the Invention
This invention is directed to a system for making a frozen food article and particularly a system which is sufficiently completely automated that no operator skills are required, and it is adaptable to coin operation.
2. Brief Description of the Prior Art
The conventional freezing device comprises a compressor for compressing a refrigerant gas which is then condensed into a liquid which is expanded to a lower pressure so that it evaporates taking up heat to cause refrigeration. The expanding refrigerant is usually in direct thermal communication with the material to be chilled so that cooling rate of the material to be chilled is limited by the steady state operation of the compressor. In some cases, a coolant is cooled by the expanding refrigerant gas. Submerged in the cooled liquid are containers which contain food material which is to be frozen. Spreen U.S. Pat. No. 1,764,653 shows a structure of this nature. In O'Neil U.S. Pat. No. 2,058,098, the expanding refrigerant cools beverage liquid so that, upon demand, a cooled beverage can be dispensed. Palmer U.S. Pat. No. 3,041,852 shows a compressor and evaporator which are contained in one unit and a separate container which receives the evaporating coolant to cool an article contained therein. This prior art is not directly pertinent, but it is generally directed to refrigeration systems for food materials. Ash U.S. Pat. No. 2,590,061 discloses a system wherein a fluid is maintained at a relatively constant temperature for dispensing to and cooling a remote vat, but this fluid is not recirculated back to the reservoir because the fluid is not a coolant. Bright U.S. Pat. No. 2,040,828 is similar to Ash, and its fermentation tank is substantially greater in volumetric capacity than the capacity of the cooling apparatus. Furthermore, while Haley U.S. Pat. No. 2,720,084 employs separate refrigeration for chilling a circulating coolant, the coolant is for air-conditioning service, and there is no teaching of a particular type of food-freezing chamber.